Maya Arnold | DOF

To automatically calculate distance between a camera and target locator.

1. Create > Measure Tools > distance Tool. Select center of camera and where the target locator will be
2. Since render with Arnold, it need to connect to CameraShape1 + Arnold Focus Distance. NOTE: It’s Not Maya default [Depth of Field > Focus Distance]
3. MEL Command line is

connectAttr -f distanceDimension1.distance cameraShape1.aiFocusDistance;

Now as you move either the target or camera, automatically calculate the focus distance for DOF! Just adjust Aperture Size.